278 Dr. 0. E. Imliof on the Microscoj^ic Fauna 



occupied with the Eritomostracan group of the Cladocera. 

 In this lake of the Engadine he found only a single species, 

 Bosmina longispina. This group of the Cladocera was inves- 

 tigated in 1877, as regards its Swiss representatives, by 

 Lutz of Berne. The basins examined lie in the environs of 

 Berne (500-600 metres above the sea-level) ; but Lutz also 

 gives some particulars as to forms which he obtained at greater 

 elevations. In lakes of the St. Gotthard Pass, at 1800 metres, 

 Sida crystallma, Bosmina longispina and B. la^vis, Ley- 

 dig, and CJiydorus sphcericus] on the Giacomo Pass, at 

 24()0 metres, AJona Uneata and Chydvrus sjdta^ricus. 



From thirty-two, cliiefly Italian, lakes, Pavcsi has brought 

 together remarkably abundant materials upon the pelagic fauna. 

 Of these thirty-two lakes, three are more than 600 metres 

 above the level of the sea : — Lago di Ledro (669) , Ceratium 

 longicorne^ Bosmina longisjnna, and Cychj^s hrevicornis ; 

 Lago di Alleghe (976), Simocephahis vetuJus, Daplinia pulex^ 

 D. longispina^ Cyclops hrevicornis^ C. serridahis, and C. gigas, 

 Lago di llitom, Vorticella sp., Simocephalus vetulus, Dajjhnia 

 ^yulex, Cyclojjs hrevicornis^ C. serrulatiiSj and Diajitomus 

 castor. 



Lastly, Asper, in his publications on the pelagic and deep- 

 water fauna, has given some statements as to microscopic forms 

 of animals. Thus, in the Klonthal lake (804 metres) he 

 found a Baplmia and a Calanid, in the Silsersee a Daphnia 

 and a Cyclopid, and in tlie lakes near the hospice of St. 

 Gotthard (2114 metres) a Daplinia and some Calanids. 



Of similar investigations beyond the borders of Switzerland 

 we have to note the following : — 



By Brandt, in the Alpine lakes of Armenia — Goktschai 

 (1904 metres), several species of Cyclops ; Tschaldyr (1958 

 metres), Daphnia hyalinaj Bythotrepdies longimamis, Lepto- 

 dora hyalina j by Wierzejski, in the lakes of the Tatra ; and 

 by Zacharias, in the two Koppenteichen (1168 and 1218 

 metres). 



Methods of investigation, — As there are generally no boats 

 on the more elevated lakes, and it would be too expensive to 

 carry a boat about with one to a great number of lakes unless 

 it were very light and divisible, we must avail ourselves of 

 other methods. The simplest method is to throw out the net, 

 which, with some practice, may be done to a distance of 10 

 metres or more ; but in tliis case one always runs the risk 

 that the net, when allowed to sink, may become entangled. 

 The loss of the net may be avoided by screwing it on to a 

 divisible rod. I employ my alpenstock, to which two some- 



